A few more facts have been coming about Vyacheslav Danilenko, the Russian scientist who has supposedly been helping Iran develop nuclear weapons.
More detail here about Danilenko's background, which seemingly shows absolutely no involvement with nuclear work at all.
But was Danilenko's real expertise, nanotechnology, useful to Iran's nuclear work nonetheless? Yes, says the Washington Post.
Danilenko’s role was judged to be so critical that IAEA investigators devoted considerable effort to obtaining his cooperation, the two officials said. The scientist acknowledged his role but said he thought his work was limited to assisting civilian engineering projects, the sources said.
This argument, that Iran is cunningly disguising much of its nuclear research as civilian, seems to be a key element of the IAEA accusations.
The Post's conclusion, too, is that Iran was not really interested in Danilenko's skills in  nanotechnology at all, but was just using him to help with the so-called "R265 generator".
There's no way to disprove this, of course, or, indeed, to prove it.
But it's interesting to note that Iran has, in fact, made enormous investments in nanotechnology, and considers itself a significant player in the field.
It's a view supported by a leading name in the nanoscience industry:
the Iranians are manufacturing everything from scientific instruments to nanomaterials. When the political issues are solved, I think a few people will be surprised by the level of sophistication of Iranian nanoscience.
Ironically enough, Iran hosted its fourth annual international nanotechnology festival just last month.